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Using WebSockets in Web apps

Using WebSockets in Web apps. Presenter: Shahzad Badar. Agenda. Who am I? WebSockets Introduction WebSockets support in Java EE 7. Who am I?. A Java evangelist working on java since 2002 Leading Pakistan JUG Working in Primatics Financials. Catch me. @shahzadbadar

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Using WebSockets in Web apps

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  1. Using WebSockets in Web apps Presenter: Shahzad Badar

  2. Agenda • Who am I? • WebSockets Introduction • WebSockets support in Java EE 7

  3. Who am I? • A Java evangelist working on java since 2002 • Leading Pakistan JUG • Working in Primatics Financials

  4. Catch me @shahzadbadar shahzadbadar@gmail.com http://www.implementsjava.com

  5. JEE 7 Theme

  6. Active JSRs • JSR 342: Java EE 7 Platform • JSR 338: Java API for RESTful Web Services 2.0 • JSR 339: Java Persistence API 2.1 • JSR 340: Servlet 3.1 • JSR 341: Expression Language 3.0 • JSR 343: Java Message Service 2.0 • JSR 344: JavaServer Faces 2.2 • JSR 345: Enteprise JavaBeans 3.2 • JSR 346: Contexts and Dependency Injection 1.1 • JSR 349: Bean Validation 1.1 • JSR 236: Concurrency Utilities for Java EE 1.0 • JSR 352: Batch Applications for the Java Platform 1.0 • JSR 353: Java API for JSON Processing 1.0 • JSR 356: Java API for WebSocket 1.0

  7. Web Socket Support In age of Web 2.0 / 3.0 , We need interactive websites • but • In the standard HTTP model, a server cannot initiate a connection with a client nor send an unrequested HTTP response to a client; thus, the server cannot push asynchronous events to clients.

  8. Why WebSocket? • HTTP was good enough for simpler World • AJAX – start of bidirectional communication (2005) • Today, Web apps demand reliable “real-time” communication with minimal latency • Social media apps • Financial applications • Online games • Collaborative Platforms • etc …

  9. Why WebSocket? • It’s hard to achieve real-time web apps, primarily due to limitations of HTTP • HTTP is half duplex ( traffic flows in only one direction at a time) • HTTP is verbose • HTTP adds latency, latency sucks

  10. HTTP Communication

  11. Simulating full-duplex • Tricks • Polling • Long-polling • HTTP Streaming • Significant resource consumption overhead • Lots of complexity • Requesting each n second • Maintaining more than one connections

  12. Polling

  13. Long Polling

  14. HTTP Streaming (Comet)

  15. HTTP Request overhead

  16. Network throughput for just the HTTP • Use case A: 1,000 clients polling every second: Network throughput is (871 x 1,000) = 871,000 bytes = 6,968,000 bits per second (6.6 Mbps) • Use case B: 10,000 clients polling every second: Network throughput is (871 x 10,000) = 8,710,000 bytes = 69,680,000 bits per second (66 Mbps) • Use case C: 100,000 clients polling every 1 second: Network throughput is (871 x 100,000) = 87,100,000 bytes = 696,800,000 bits per second (665 Mbps)

  17. WebSocket to rescue • TCP based, bi-directional, full-duplex messaging • Capable of sending both UTF-8 string and binary frames in any direction at the same time • Operating from a single socket across the web • As part of HTML5, the application of the client interface will become native to all modern browsers • To establish a Web Socket connection, the browser or client simply makes a request to the server for an upgrade from HTTP to a Web Socket

  18. HTML5 Web Sockets! • Use case A: 1,000 clients receive 1 message per second: Network throughput is (2 x 1,000) = 2,000 bytes = 16,000 bits per second (0.015 Mbps) [was 6.6 Mbps] • Use case B: 10,000 clients receive 1 message per second: Network throughput is (2 x 10,000) = 20,000 bytes = 160,000 bits per second (0.153 Mbps) [was 66 Mbps] • Use case C: 100,000 clients receive 1 message per second: Network throughput is (2 x 100,000) = 200,000 bytes = 1,600,000 bits per second (1.526 Mbps) [was 665 Mbps]

  19. Comparison of the unnecessary network throughput overhead

  20. Latency comparison

  21. Web Sockets - Win • HTML5 Web Sockets can provide a 500:1 or—depending on the size of the HTTP headers—even a 1000:1 reduction in unnecessary HTTP header traffic • 3:1reduction in latency.

  22. “Reducing kilobytes of data to 2 bytes…and reducing latency from 150ms to 50ms is far more than marginal. In fact, these two factors alone are enough to make Web Sockets seriously interesting to Google.”

  23. Web Sockets The WebSocket specification defines an API establishing "socket" connections between a web browser and a server. In plain words: There is an persistent connection between the client and the server and both parties can start sending data at any time.

  24. Establishing a connection

  25. Handshake Request/Response

  26. Establishing a connection

  27. WebSocket Lifecycle Connected ! Client Server open open message message error message message close Disconnected

  28. Getting Started • You open up a WebSocket connection simply by calling the WebSocket constructor: varconnection = new WebSocket('ws://localhost:8080/chat', ['soap', 'xmpp']); Notice the ws:. This is the new URL schema for WebSocket connections. There is also wss: for secure WebSocket connection the same way https: is used for secure HTTP connections.

  29. Getting Started // When the connection is open, send some data to the server connection.onopen= function () { connection.send('Ping'); // Send the message 'Ping' to the server }; // Log errors connection.onerror= function (error) { console.log('WebSocket Error ' + error); }; // Log messages from the server connection.onmessage= function (e) { console.log('Server: ' + e.data); }; //close connection connection.close();

  30. Monitoring WebSockets Traffic

  31. WebSockets on Server • Javascript: socket.io • C++: libwebsockets • Errlang: Shirasu.ws • Java: Jetty, Grizlly • Node.JS: ws • Ruby: em-websocket • Python: Tornado, pywebsocket • PHP: Ratchet, phpws

  32. Browser Support for WebSockets

  33. Java EE 7 – WebSockets Support • The Java EE platform includes the Java API for WebSocket (JSR-356), which enables you to create, configure, and deploy WebSocket endpoints in web applications. • The WebSocket client API specified in JSR-356 also enables you to access remote WebSocket endpoints from any Java application. • The Java API for WebSocket consists of the following packages: • The javax.websocket.server package contains annotations, classes, and interfaces to create and configure server endpoints. • The javax.websocket package contains annotations, classes, interfaces, and exceptions that are common to client and server endpoints.

  34. Creating and Deploying a WebSocket endpoint • The process for creating and deploying a WebSocket endpoint is the following: • Create an endpoint class. • Implement the lifecycle methods of the endpoint. • Add your business logic to the endpoint. • Deploy the endpoint inside a web application.

  35. Java WebSocket Implementations

  36. Basic API Tour

  37. Hello World Server public class HelloServer extends Endpoint { @Override public void onOpen(Session session, EndpointConfig configuration) { session.addMessageHandler( new MessageHandler.Whole<String>() { public void onMessage(String name) { try { session.getBasicRemote().sendText(“Hello “ + name); } catch (IOException ioe) { // Handle failure. } } }); }}

  38. Hello World Client public class HelloClient extends Endpoint { @Override public void onOpen(Session session, EndpointConfig configuration) { try {session.getBasicRemote().sendText("Hello you!"); } catch (IOExceptionioe) { . . . } }}

  39. Client Server Configuration ServerContainerserverContainer = (ServerContainer) servletContext.getAttribute( “javax.websocket.server.ServerContainer”); ServerEndpointConfigserverConfiguration = ServerEndpointConfig.Builder.create( HelloServer.class, "/hello").build(); serverContainer.addEndpoint(serverConfiguration); ... URI clientURI = new URI("ws://myserver.com/websockets/hello"); WebSocketContainer container = ContainerProvider.getWebSocketContainer(); ClientEndpointConfigclientConfiguration = ClientEndpointConfig.Builder.create().build(); container.connectToServer(HelloClient.class, clientConfiguration, clientURI);

  40. Sending the Message * additional flavors: by completion, by future

  41. Receiving the Message

  42. POJO + Annotations

  43. Hello World Annotations @ServerEndpoint("/hello")public class HelloBean {@OnMessage public String sayHello(String name) { return “Hello “ + name; }}

  44. WebSocket Annotations

  45. @ServerEndpoint attributes

  46. Custom Payloads @ServerEndpoint( value="/hello",encoders={MyMessage.class}, decoders={MyMessage.class})public class MyEndpoint { . . .}

  47. Custom Payloads – Text public class MyMessage implements Decoder.Text<MyMessage>, Encoder.Text<MyMessage> { private JsonObjectjsonObject; public MyMessagedecode(String s) {jsonObject = new Json.createReader( new StringReader(s)).readObject(); return this; } public booleanwillDecode(String string) { return true; // Only if can process the payload } public String encode(MyMessagemyMessage) { return myMessage.jsonObject.toString(); }}

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